By Scott McCarthy It is accepted certainty that Evan Ferguson will leave Brighton at some point in the next few years, potentially as soon as this summer’s transfer window. But for Chelsea? He would have to be mad to swap the American Express Stadium for Stamford Bridge. And if his fledgling career so far has shown us anything, it is that Ferguson is not mad. Far from it. He is an older, wiser head on young shoulders. He makes remarkably sensible decisions based on what is good for his career rather than his bank balance. Ferguson wants to develop into the best player he can. To that end, he a…